Relations of the derived GP parameters to the RV uncertainty. Top: derived GP length scale as a function of the ratio of the standard deviation of the stellar activity signal over the RV uncertainty or jitter. Note that only GP-only fits that had at least moderate significance (with ∆ ln 𝒵 > 2.5) compared to a white noise model that includes only jitter have been used. The curves were computed by applying a median filter with a window size incorporating 50 simulations. The red curve assumes a fixed jitter of σ_jitter = 0 m s⁻¹ and changes the ratio σ_model/σ_RV, the black curve assumes a fixed jitter of σ_jitter = 1.2 m s⁻¹ and changes the ratio σ_model/σ_RV, and the blue curve assumes a fixed uncertainty of σ_RV = 0.3 m s⁻¹ and changes the ratio σ_model/σ_jitter. The colored shaded area shows the appropriate inter-quartile range. The vertical dotted line represents a ratio of 1. The horizontal dashed line represents the simulated spot lifetime. Bottom: analogous to the top plot, but for the GP rotation period.